init.lua

local curtain_colors = { --name, color, colorize(hex or color name:intensity(1-255))
{'Black', 'black', '#26231f:200'},
{'Blue', 'blue', '#284965:200'},
{'Brown', 'brown', '#65493f:200'},
{'Cyan', 'cyan', '#3a8d94:200'},
{'Dark Green', 'dark_green', '#485831:200'},
{'Dark Grey', 'dark_grey', '#464342:200'},
{'Green', 'green', '#739251:200'},
{'Grey', 'grey', '#85817e:200'},
{'Magenta', 'magenta', '#b74679:200'},
{'Orange', 'orange', '#bb6c3e:200'},
{'Pink', 'pink', '#a2655f:200'},
{'Red', 'red', '#893734:200'},
{'Violet', 'violet', '#5e3170:200'},
{'White', 'white', '#bcb2a6:200'},
{'Yellow', 'yellow', '#c0a342:200'},
}

for i in pairs(curtain_colors) do
		local name = curtain_colors[i][1]
		local color = curtain_colors[i][2]
		local hex = curtain_colors[i][3]
		
		minetest.register_node("curtains:curtain_"..color, {
		description = color:gsub("^%l", string.upper).." Curtain",
		walkable = false,
		tiles = {"homedecor_curtain.png^[colorize:"..hex},
		inventory_image = "homedecor_curtain.png^[colorize:"..hex,
		wield_image = "homedecor_curtain.png^[colorize:"..hex,
		drawtype = "signlike",
		paramtype2 = "colorwallmounted",
		groups = {dig_immediate=3, flammable=3},
		selection_box = {type="wallmounted"},
		on_rightclick = function(pos, node, _, itemstack)
			minetest.set_node(pos, {name="curtains:curtain_open_"..color, param2=node.param2})
			return itemstack
		end
	})

	minetest.register_node("curtains:curtain_open_"..color, {
		tiles = {"homedecor_curtain_open.png^[colorize:"..hex,},
		drawtype = "signlike",
		paramtype2 = "colorwallmounted",
		walkable = false,
		groups = {dig_immediate=3, flammable=3, not_in_creative_inventory=1},
		selection_box = {type="wallmounted"},
		drop = "curtains:curtain_"..color,
		on_rightclick = function(pos, node, _, itemstack)
			minetest.set_node(pos, {name="curtains:curtain_"..color, param2=node.param2})
			return itemstack
		end
	})

	minetest.register_craft({
		output = "curtains:curtain_"..color.." 2",
		recipe = {{"", "wool:"..color, ""}}
	})
end